WASHINGTON -- Speaking to the families of dead soldiers, Vice President Joe Biden on Friday delivered an emotional retelling of his own family tragedy, the death of his wife and daughter in a car crash 40 years ago, saying the experience helped him understand why people commit suicide.

Biden said the shock and pain of the deaths in 1972, shortly after he was first elected to the Senate, was a “black hole you feel in your chest, like you're being sucked back into it.”

“It was the first time in my career, my life, I realized someone could go out – and I probably shouldn't say this with the press here, but – no, but it's more important. You're more important. For the first time in my life I understood how someone could consciously decide to commit suicide,” Biden said. “Not because they were deranged, not because they were nuts; because they'd been to the top of the mountain and they just knew in their heart they'd never get there again, that it was never going to be that way ever again. That's how an awful lot of you feel.”

Biden addressed a group associated with the Tragedy Assistance Program for Survivors, a national nonprofit group that supports friends and families of service members killed in action.

Biden has previously spoken about the accident, although he rarely describes the emotional aftermath in such detail. He described how he heard the news while in Washington.

“I was down in Washington hiring my staff, and I got a phone call saying that my family had been in an accident. And just like you guys know by the tone of a phone call – you just knew, didn't you? You knew when they walked up the path. You knew when the call came. You knew. You just felt it in your bones something bad happened,” Biden said.

“And I knew. I don't know how I knew. But the call said my wife was dead, my daughter was dead, and I wasn't sure how my sons were going to make it. They were Christmas shopping, and a tractor-trailer broadsided them and in one instant killed two of them and – well.”

Biden, a practicing Roman Catholic, said he was so angry he cried out in the Capitol. “I remember being in the Rotunda, walking through to get to the plane to get home, to get to identify the – anyway. But I remember looking up and saying, ‘God!’ It was if I was talking to God myself: ‘You can't be good! How can you be good?’”

Biden said he was pulled out of his grief with the help of his mother, his sister and, eventually, his second wife, Jill Biden, whom he married five years later. “This woman literally saved my life,” he said.

“There will come a day, I promise you, and your parents as well, when the thought of your son or daughter or your husband or wife brings a smile to your lips before it brings a tear to your eye. It will happen,” he said. “My prayer for you is that day will come sooner or later. But the only thing I have more experience than you in is this: I'm telling you it will come.”